DEC LK201 Disassembly, Bolt Modding, Restoration and Conversion [In Progress]

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ifohancroft

30 Jul 2021, 14:13

It is not done yet, but I am starting the post already, so I don't lose the pictures and as a way to force myself to finish it. When it's done, the title will be changed and this "disclaimer" will be removed. To be honest, I am not entirely sure if it makes sense for everything to be in a single post or if I should instead make a separate disassembly/reassembly guide, make a post about bolt modding and restoring the board (although it's in a damn good condition, so regarding restoration, it may just need some cleaning and slight retrobrighting) and a separate conversion post. However, I can always split this post when it's done. For now, I'll just keep everything in one place.

I got a free DEC LK201 from wheybags exactly a week ago. It's my first retro keyboard and I feel like it's a good one to start with, as it has many interesting things about it, depending on what you are into:

1. It's the keyboard that popularized the inverted-T arrow cluster (according to the wiki).
2. It's the keyboard of the DEC VT-220, which is one of the most popular terminals, and one of the most emulated terminals by terminal emulators.
3. I liked how it looked and I wanted to try its leafsprings (it's leafspring over membrane)

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I got it and I liked it but it felt a bit scratchy, like it was dirty, so I decided to open it and take a look (will see when I'm done with the keyboard if it actually feels any better).

Now, to the actual part of this post.

Disassembly:

Disclaimer: I am not responsible if you break your keyboard by following this disassembly guide.

Remove the two bolts on the top of the board's underside using a 6mm socket wrench:

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Turn the keyboard back again and lift the upside of the top of the case up and towards you. It's being hold only on its bottom, so it lifts up like it's on hinges.

Now you just need to free the plastic tabs on the bottom of the top of the case and you can remove it. You can either push them with something like a spudger or just wiggle the case around until they come free. You can basically push forward, turn the top downward a bit, and lift it.

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Now, the board's metal plate is being held by the bottom of the case from the left side, so you need to push it to the right.

Here you can clearly see how it's being held form the left side:

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Here, circled in red you can see all the places it's being held, but also notice the part marked in blue:

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The part marked in blue holds the plate from the underside, preventing it to slide to the right, so you need to push it down with a spudger while you are pushing the plate.

Here's how it looks when the plate is still on:

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Regardless of whether you are pushing the part marked in blue down with a spudger or not, don't try to push the plate to the right while the keyboard is laying flat on its back. It won't work and you'll cut your finger:

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Let gravity help you.

To remove the plate from the case bottom, turn the keyboard on its right side, while holding it with your left hand.
With your right hand, push the part circled in blue downwards (technically now it's to your left) with the pointy end of a spuder, while with your left hand's thumb, push the plate to the right (now it's technically downwards) and it will move easily.

Now you just need to detach the cable from the keyboard and you can remove it from the bottom of the case:

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I still need to shoot and add removing the PCB from the plate/membrane assembly, but spoiler alert (it's done by unbending the legs of a couple of components that go through the PCB, then releasing the membrane from the PCB and then pushing the PCB to the right, while holding down a part (like the one marked in blue above) with a spudger



Reassembly:

I need to take photos and add them here.



Bolt Modding:

I was surprised to see that the underside of the plate, looks like a Model M:

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What I mean by that, is that everything is held together with this plastic pegs (can't remember the correct word atm) and they start breaking with time.

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Those plastic pegs are basically the "legs" of these plastic parts that the keycaps mount on:

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The plastic parts are mounted to the plate through their legs that are fixed at the back of it. Besides for mounting keycaps on them, they also serve to hold the leafsprings in place.

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I forgot to measure how thick the walls of the plastic parts from which the legs protrude are, but they look pretty thin. To fix the keyboard as some have already broken off, I would basically need to bolt mod it. Using screws from the underside, screwing them through the plate and through the holes in the legs of the leafsprings into the plastic parts' bottoms. I would soon get a bag of M1 screws and hope they are small enough. If not, I found out smaller screws exist and some places are selling M0.8 and M0.6 screws.

If none of those sizes work, I have no idea how I will fix the leafsprings and the plastic parts to the plate.

I need to buy screws, see if they are small enough and do the actual bolt modding if they are, shoot it and add it to this section



Conversion:

Correct me if I'm wrong, but from my own research, it looks like it doesn't work with Soarer's converter and no one has converted it yet. However, I found this, which will help me with the conversion: https://www.vt100.net/keyboard.html



Retrobrigthing:

Needs to be done.



Interesting Findings:

Apparently, the function keys' label is an insert, and there is another one below it:

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There is this I guess manufacturing date legend, on the inside of the bottom of the case, but I am not entirely sure how to read it:

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MMcM

31 Jul 2021, 00:49

ifohancroft wrote:
30 Jul 2021, 14:13
no one has converted it yet.
Have a look here.
ifohancroft wrote:
30 Jul 2021, 14:13
I am not entirely sure how to read it:
March 3, 1989, second shift, I believe.

User avatar
ifohancroft

31 Jul 2021, 01:38

MMcM wrote:
31 Jul 2021, 00:49

Have a look here.

Thank you! I really need to learn to use the search function on the forum :D
MMcM wrote:
31 Jul 2021, 00:49
March 3, 1989, second shift, I believe.
Thank you!

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